Contaminant transport by human passage through an air curtain separating two sections of a corridor: Part I – Uniform ambient temperature

• Published in: Energy and buildings Vol. 236; p. 110818
• Main Authors: Jha, Narsing K., Frank, D., Linden, P.F.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.04.2021; Elsevier BV
• Subjects: Air curtains; Air pollution; Air temperature; Ambient temperature; Brines; Contaminants; Cylinders; Effectiveness; Fresh water; Heat transfer; Human traffic; Particle image velocimetry; Pollution transport; Walking; Effectiveness; Heat transfer; Air curtains; Human traffic
• ISSN: 0378-7788; 1872-6178
• DOI: 10.1016/j.enbuild.2021.110818

[Display omitted] Air curtains are commonly used as separation barriers to reduce exchange flows through an open door of a building. Here, we investigate the effectiveness of an air curtain to prevent the transport of contaminants by a person walking along a corridor from a dirty zone into a clean zone. We conduct small-scale waterbath experiments with fresh water, brine and sugar solutions, with the brine acting as a passive tracer for the contaminant transport in the wake of a person. A cylinder representing a moving person is pulled between two fixed points in the channel across the air curtain. We observe that the air curtain can prevent up to 40% of the contaminant transport due to the wake of a moving person. We propose a new way to evaluate the performance of an air curtain in terms of the deflection modulus and the effectiveness defined for this iso-density situation, similar to quantities typically used for the case where the fluid densities in the two zones are different. We observe that the air curtain has an optimal operating condition to achieve a maximum effectiveness. Dye visualisations and time-resolved particle image velocimetry of the air curtain and the cylinder wake are used to examine the re-establishment process of the planar jet after its disruption by the cylinder and we observe that some part of the wake is separated by the re-establishing curtain. We observe that the exchange flux peaks after the cylinder passes the air curtain and reduces to a typical value after the re-establishment of the curtain.